Celgene Acquires Entremed Inc.'s Rights to Thalidomide.

ROCKVILLE, Md. and WARREN, N.J.--(BUSINESS WIRE)--Dec. 10, 1998--

Collaborative Effort Expedites Drug Development for Cancer Patients

EntreMed Inc. (NASDAQ:ENMD) and Celgene Corp. (NASDAQ:CELG) Thursday announced the signing of a collaborative sublicensing agreement for the advancement of thalidomide drug development.

Under the agreement, Celgene has acquired exclusive worldwide rights to EntreMed's patents and technology for thalidomide, as well as United States Food and Drug Administration (FDA) orphan drug designations achieved by EntreMed.

A joint steering committee comprised of scientists and executives from both companies has been formed to ease the transfer of sponsorship for ongoing clinical trials of thalidomide in a variety of cancer indications.

Under a letter of intent with the NCI, EntreMed had recently broadened the scope of its thalidomide clinical trials to include new investigational studies in non-small cell lung cancer, metastatic renal cell cancer, and head and neck cancer which will build upon current studies in primary brain cancer, prostate cancer, Kaposi's sarcoma, and breast cancer.

Celgene will now have responsibility for present and future clinical research on thalidomide and will additionally assume primary responsibility for the on-going relationship with the National Cancer Institute (NCI) for clinical trials of thalidomide.

Celgene has been developing THALOMID(TM) (thalidomide) for the treatment of a number of autoimmune and inflammatory diseases. In July 1998, Celgene received FDA clearance to market and sell THALOMID(TM) for the treatment of erythema nodosum leprosum (ENL), an inflammatory complication of leprosy.

Celgene is currently investigating THALOMID(TM) in several oncological indications, including multiple myeloma, and in HIV/AIDS-related conditions, and Crohn's disease.

According to Celgene Chairman and Chief Executive Officer, John Jackson, "This agreement significantly expands the intellectual property rights Celgene holds on thalidomide to include antiangiogenesis as well as expanding our outside collaborations and development of THALOMID(TM) in oncology.

Our agreement with EntreMed will expedite development of this novel drug as a therapeutic in life-threatening cancers where current therapy is often inadequate," said Jackson.

Dr. John W. Holaday, EntreMed chairman and chief executive officer commented on the agreement, "This collaboration is an extremely positive one with direct and swift benefits to Celgene, EntreMed and cancer patients throughout the country.

"EntreMed will receive royalty payments beginning immediately and the revenue produced by this agreement will assist EntreMed in its development of the antiangiogenic agent Endostatin(TM) protein as we prepare for initiation of clinical trials in 1999."

It is important to note that thalidomide can cause severe birth defects or death to an unborn baby if taken during pregnancy. The drug should never be used by women who are pregnant or who could become pregnant while taking the drug.

Because of this toxicity and in an effort to make the chance of fetal exposure to thalidomide as small as possible, THALOMID(TM) must be accessed through physicians and pharmacies participating in a program called the System for Thalidomide Education and Prescribing Safety, or S.T.E.P.S.(TM).

In all patients, thalidomide has the potential to cause nerve damage that may be permanent, drowsiness/somnolence, dizziness/orthostatic hypotension, neutropenia, increased viral load and hypersensitivity reactions.

Celgene Corp., headquartered in Warren, is engaged in the development of pharmaceuticals and agrochemicals.

Rockville-based EntreMed Inc., The Angiogenesis Company(TM), is a leader in the field of antiangiogenesis research, which involves the inhibition of abnormal blood vessel growth recently associated with a broad range of diseases.

The Company's strategy is to accelerate development of its core technologies through collaborations and sponsored research programs with university medical departments, research companies and government laboratories.

For further information, please visit the EntreMed web site at www.entremed.com. Statements herein that are not descriptions of historical facts are forward-looking and subject to risk and uncertainties.

Actual results could differ materially from those currently anticipated due to a number of factors, including those set forth in the Company's Securities and Exchange Commission filings under "Risk Factors," including risks relating to the early stage of products under development; uncertainties relating to clinical trials; dependence on third parties; future capital needs; and risks relating to the commercialization, if any, of the Company's proposed products (such as marketing, safety, regulatory, patent, product liability, supply, competition and other risks).